The girl was brought to Israel in grave condition last week, with a serious infection of the digestive tract which affected her nervous system. She was returned to Gaza a day later after Israeli doctors concluded they could not help her.

A statement from Haniyeh's office quoted by AP said the girl, named Amal, died at a children's hospital in Gaza.

Amal's father wrote on his Facebook page that she had suffered brain damage.

Haniyeh's office declined comment on the granddaughter's seeking treatment in Israel, but a family friend said the move had no political significance.

Palestinian Authority Chairman Mahmoud Abbas offered his condolences to Haniyeh over the death of his granddaughter, reported the Ma’an news agency.

Hamas and Abbas’s Fatah faction have been at odds since Hamas violently took control of Gaza in 2007, setting up its own government there and cracking down on Fatah officials who reside in the territory.